1. Field of the Invention
This invention relates to a control valve device for the control of a consumer, such as a dual-action consumer. The control valve device has a control valve that controls the connection of a pressure fluid line that forms the connection of the admission side of the consumer with a pump and an additional pressure fluid line that forms the return side of the consumer with a reservoir. The control valve device has a regeneration function by means of which the return side of the consumer can be connected with the admission side of the consumer.
2. Technical Considerations
Control valve devices are used for the control of consumers in mobile machines, for example to control a stick cylinder of an excavator. To prevent cavitation on the admission side of the consumer and to achieve an increased speed of movement of the consumer that requires a flow that exceeds the discharge flow delivered by the pump, control valve devices are provided with a regeneration function. The regeneration function connects the return side of the consumer with the admission side. As a result of which, on the admission side of the consumer, the flow of pressure fluid flowing out of the return side of the consumer is available in addition to the discharge flow delivered by the pump.
A control valve device is described in DE 198 44 699 A1. The regeneration function is formed by regeneration lines, each of which connects a return line that leads from the control valve to the reservoir with the respective admission side of the consumer. Check valves that open to the admission side of the consumer are located in these regeneration lines. For the regeneration function, the return line is shut off by means of a valve device located in the return line downstream of the connections of the regeneration lines. When the regeneration function is active, the pressure fluid that is being discharged from the return side of the consumer flows via the control valve and the return line (which is shut off by means of the valve device) into the regeneration line (which is in communication with the admission side of the consumer) and thus to the admission side of the consumer. However, as a result of this routing of the flow of pressure fluid of the regeneration function via the control valve, long flow paths are required. This leads to high line losses and thus to a low efficiency of the regeneration function. On account of the regeneration lines, the regeneration function also requires a great deal of construction effort and expense. Moreover, with a regeneration function of this type not all of the pressure fluid that is discharged from the return side can be transported to the admission side. This means that only a limited increase in the speed of the consumer can be achieved in the regeneration function.
Therefore, it is an object of this invention to provide a control valve device of the general type described above but that makes possible a regeneration function with an improved increase in the speed of the consumer and low line losses and therefore high efficiency.